"The BOJ can buy whatever amount of ETFs and REITs it can. It can even buy government bonds more forcefully, as if it were to buy the entire amount in markets," Hamada said in an interview with Reuters.

"There are also other various measures, although the BOJ must also be mindful of the drawbacks."

According to Credit Suisse, the BOJ's balance sheet as a proportion of the nation's GDP will far outstrip that of the other major central banks (excluding the SNB) within the next two years. This is uncharted territory - nothing of this magnitude has been tried before in a developed economy. As a result, dollar/yen is at 99 (the yen is down some 25% over the past 6 months) and Japan's stock market just hit a 5-year high.